The invention relates to an implement interface for attaching an implement to the rear or front of a vehicle, such as an industrial or agricultural tractor.
Industrial or agricultural vehicles, such as tractors, in addition to performing transport tasks, are primarily used for carrying out tasks in the field. For this purpose, a suitable implement is attached to the working vehicle.
Since the tractor must be coupled to various implements in order to carry out different tasks, the implement interface between the motor vehicle and the implement is of particular importance. The term implement interface refers to all devices which are required for coupling the implements to the vehicle and, if so required, for supplying them with power.
A so-called three-point hitch, e.g., as defined by ISO 730 or DIN 9674, is a conventional implement interface provided on most modern tractors and similar agricultural vehicles includes. Such a hitch usually includes two lifting arms that are connected to one another by means of a lifting shaft, and a corresponding hydraulic lifting cylinder engages each of the lifting arms. Each lifting arm is connected to a corresponding lower linkage by means of a lifting rod or a lifting spindle, and the lower linkage carries a lower coupler. In addition, the three-point hitch includes an upper linkage with a third, central upper coupler.
Such a three-point hitch makes it possible to easily and rapidly attach implements to the tractor. First, the tractor is moved near the parked implement. The implement is then coupled to corresponding receptacles of the implement interface so that the vehicle and the implement form a functional unit. If so required, a power take-off shaft of the vehicle is connected to an input shaft of the implement. In addition, electric and hydraulic connections for transmitting power and signals can be provided between the working vehicle and the implement. The implement can be raised and adjusted with respect to its height within a limited range by actuating the lifting cylinders in order to move the implement between its transport position and the desired working position. In this case, the implement frequently does not require a separate chassis. Despite the fact that the three-point hitch can be used for many tasks, its functions are still limited.
objective of the present invention is to provide an implement interface which can perform functions not performed by a conventional three-point hitch.
These and other objects are achieved by the present invention wherein an implement interface includes a telescopic boom which is mounted on a vehicle chassis, frame or body and which is pivoted about a substantially horizontal axis. The boom includes an outer housing and an arm which slides telescopically in the housing. Lower linkages of a conventional three-point hitch are coupled to a free end of the boom. An extendable upper linkage is directly or indirectly coupled to the boom. This results in a pivotable implement interface which can be adjusted with respect to its height and which can perform all the tasks normally performed by a conventional three-point hitch. The telescopic boom makes it possible to lift an implement (or the like) very high compared to the lifting high of a normal 3-point hitch. This makes it possible to lift the implement and to load it on a trailer. Implements can be moved with expanded degrees of freedom and an expanded lifting range. With this interface, the vehicle may be used as a conventional towing vehicle with a customary implement interface or as a functional loader. If the implement is a plow, the plow can be raised after the normal working operation (plowing) to such a degree that the implement can be deposited on a trailer or an elevated storage platform without additional means.
Because of the simple and rapid loading of the implement, the vehicle can be moved rapidly between different working locations. For example, the implement may be loaded onto a trailer after the work at one location is completed, and then the trailer is attached to the vehicle and driven to a new location at a high speed. An implement may be raised to an elevation such that the implement can be placed on shelves or trailers without first separating the implements from the three-point hitch.
Hitch lower linkages, and if required, other attachments and towing implements, may be coupled or mounted on a carrier which is attached a free end of the boom. Different carriers can be mounted on the boom in order to adapt to different requirements, without modification or changing of the boom.
Preferably, the interface includes a locking device which is operable to selectively fix the free end of the boom and/or the carrier relative to the vehicle chassis, such as when the boom is in a lowered work position. If this locking device is engaged, the hitch forces are transmitted directly to the rear axle or to the vehicle chassis, without being transmitted to the boom. Thus, the boom can be designed for relatively small loads.
The interface may include a lifting arm is coupled to the free end of the boom or to the carrier, and the lifting arm can be vertically pivoted by a lifting cylinder. This lifting arm is connected to one of the lower linkages by lifting brace, rod or cylinder, and the lower linkages retain their conventional functions.
Additional attachments may be coupled to the free end of the boom or on the carrier so that towed implements or trailers can be attached to the vehicle. For example, a trailer drawbar may be grasped while on the ground and hydraulically moved into the operating position. Electric and/or hydraulic connections which are used to transmit power or signals may also be provided on the boom or the carrier.
In a preferred embodiment, the boom may guide a arm which is coupled to the upper linkage, and which can be displaced in the longitudinal direction of the boom. An upper linkage coupled to the free end of the arm may be extended and retracted by means of the arm, and the arm can be oriented essentially parallel to the boom. The telescopic guidance of the arm in the boom results in a stable double-telescopic rear interface.
Preferably, double-acting hydraulic piston/cylinder units are used to pivot the boom and extend the arm, and are coupled between the vehicle chassis and the boom, and between the boom and the arm, and are supplied with hydraulic fluid from the vehicle hydraulic system. Preferably, two pivoting cylinders are arranged parallel to one another, and have one end coupled to the vehicle chassis and an upper end coupled to the boom housing so that the implement can be moved vertically.
An upper linkage cylinder may be integrated into the upper linkage and/or into the arm in order to extend and retract the coupler of the upper linkage relative to the boom. The length of the upper linkage may be adjusted with such an upper linkage. In this case, the implement may be maintained in a horizontal position within a lower lifting range by correspondingly controlling the upper linkage cylinder, and within an upper lifting range by correspondingly controlling the arm cylinder.
In order to raise the implement interface to a substantial height, the boom of one preferred embodiment includes a housing which is pivotally coupled to the vehicle chassis and an extendable insert that is guided by the housing and is used to extend the length of the boom. A carrier is preferably mounted within the free end of the insert and carries a three-point hitch and, if required, other attachments and towing implements.
Preferably, the insert is telescopically guided within the housing, and both have rectangular profiles for structural rigidity. In certain applications, the boom may have three sections that are concentrically inserted into one another. With such a telescopic boom, the coupling of implements and digging with an earth scoop can be achieved by horizontal extension and retraction of the telescopic arm, without having to move the tractor. A hydraulic piston/cylinder unit may be coupled between the housing of the boom and an extendable insert or between the respective sections of the boom in order to extend and retract the sections.
An adapter can be mounted on the three-point hitch and used to receive special implements that require special implement interfaces and which cannot be attached to a conventional three-point hitch. With an appropriate adapter, this interface may be used as a conventional front-end loader, and front-end loader tools, such as an earth scoop, the fork of a forklift, etc., can be attached to the three-point hitch.
Preferably, the pivoting system is designed so that the coupling plane is maintained vertical or in another desired alignment independently of the incline of the boom, so that the implement maintains a certain desired alignment relative to the ground during a series of tasks, even if the boom has been pivoted vertically. A level control unit is provided for controlling the pivoting cylinder, arm cylinder, upper linkage cylinder, lifting cylinder and/or extension cylinder so that the implement is maintained in the desired alignment relative to the ground independently of the incline of the boom. The implement alignment and position can be monitored by a suitable sensor in order to determine an actual value signal for the level control.